// Copyright 2018 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef V8_OBJECTS_JS_PROMISE_H_
#define V8_OBJECTS_JS_PROMISE_H_

#include "src/objects/js-objects.h"
#include "src/objects/promise.h"

// Has to be the last include (doesn't have include guards):
#include "src/objects/object-macros.h"

namespace v8 {
namespace internal {

    // Representation of promise objects in the specification. Our layout of
    // JSPromise differs a bit from the layout in the specification, for example
    // there's only a single list of PromiseReaction objects, instead of separate
    // lists for fulfill and reject reactions. The PromiseReaction carries both
    // callbacks from the start, and is eventually morphed into the proper kind of
    // PromiseReactionJobTask when the JSPromise is settled.
    //
    // We also overlay the result and reactions fields on the JSPromise, since
    // the reactions are only necessary for pending promises, whereas the result
    // is only meaningful for settled promises.
    class JSPromise : public JSObject {
    public:
        // [reactions_or_result]: Smi 0 terminated list of PromiseReaction objects
        // in case the JSPromise was not settled yet, otherwise the result.
        DECL_ACCESSORS(reactions_or_result, Object)

        // [result]: Checks that the promise is settled and returns the result.
        inline Object result() const;

        // [reactions]: Checks that the promise is pending and returns the reactions.
        inline Object reactions() const;

        DECL_INT_ACCESSORS(flags)

        // [has_handler]: Whether this promise has a reject handler or not.
        DECL_BOOLEAN_ACCESSORS(has_handler)

        // [handled_hint]: Whether this promise will be handled by a catch
        // block in an async function.
        DECL_BOOLEAN_ACCESSORS(handled_hint)

        int async_task_id() const;
        void set_async_task_id(int id);

        static const char* Status(Promise::PromiseState status);
        V8_EXPORT_PRIVATE Promise::PromiseState status() const;
        void set_status(Promise::PromiseState status);

        // ES section #sec-fulfillpromise
        V8_EXPORT_PRIVATE static Handle<Object> Fulfill(Handle<JSPromise> promise,
            Handle<Object> value);
        // ES section #sec-rejectpromise
        static Handle<Object> Reject(Handle<JSPromise> promise, Handle<Object> reason,
            bool debug_event = true);
        // ES section #sec-promise-resolve-functions
        V8_WARN_UNUSED_RESULT static MaybeHandle<Object> Resolve(
            Handle<JSPromise> promise, Handle<Object> resolution);

        DECL_CAST(JSPromise)

        // Dispatched behavior.
        DECL_PRINTER(JSPromise)
        DECL_VERIFIER(JSPromise)

        DEFINE_FIELD_OFFSET_CONSTANTS(JSObject::kHeaderSize,
            TORQUE_GENERATED_JSPROMISE_FIELDS)

        static const int kSizeWithEmbedderFields = kSize + v8::Promise::kEmbedderFieldCount * kEmbedderDataSlotSize;

        // Flags layout.
        // The first two bits store the v8::Promise::PromiseState.
        static const int kStatusBits = 2;
        static const int kHasHandlerBit = 2;
        static const int kHandledHintBit = 3;
        class AsyncTaskIdField : public BitField<int, kHandledHintBit + 1, 22> {
        };

        static const int kStatusShift = 0;
        static const int kStatusMask = 0x3;
        STATIC_ASSERT(v8::Promise::kPending == 0);
        STATIC_ASSERT(v8::Promise::kFulfilled == 1);
        STATIC_ASSERT(v8::Promise::kRejected == 2);

    private:
        // ES section #sec-triggerpromisereactions
        static Handle<Object> TriggerPromiseReactions(Isolate* isolate,
            Handle<Object> reactions,
            Handle<Object> argument,
            PromiseReaction::Type type);

        OBJECT_CONSTRUCTORS(JSPromise, JSObject);
    };

} // namespace internal
} // namespace v8

#include "src/objects/object-macros-undef.h"

#endif // V8_OBJECTS_JS_PROMISE_H_
